1. Technical Field
Embodiments of the present invention generally relate to modem communications. More particularly, embodiments relate to modem receivers having re-configurable decoding schemes.
2. Discussion
As the content available on the Internet continues to grow and increase in complexity, the desirability of broadband communication becomes increasingly apparent. Asymmetric digital subscriber line (ADSL) modems convert the copper twisted-pair telephone lines in the plain-old telephone system (POTS) into access paths for multimedia and high speed communication, and have rapidly evolved in an effort to meet the need for broadband communications. Conventional ADSL modems have modem receivers that are implemented in hardware such as application-specific integrated circuit (ASIC) technology. While certain approaches to hardware-based modem receivers have been effective in the past, a number of challenges remain.
A particular challenge relates to decoding in the modem receiver. Specifically, traditional hardware-based modem receivers receive an incoming data signal and decode the incoming data signal in accordance with a particular decoding scheme (or algorithm). In general, the more complex the implemented decoding scheme, the more reliable the decoding. Highly reliable decoding translates into higher data rates for a given loop length, where loop length is defined as the distance between the customer premises equipment (CPE) and the central office (CO).
While data rates have continued to increase due to the availability of more and more reliable encoding schemes, there has been a concurrent trend for ADSL services to cover both short-loop/high-data rate and long-loop/low-data rate customers. For example, the same ADSL service may be required to provide Internet access to CPE that is located close to the servicing CO (i.e., high data rate), as well as CPE located far away from the CO (i.e., lower data rate). The conventional hardware-based ADSL approach to implementing the modem receiver may be unable to achieve this goal, however, due to a lack of programmability. Specifically, the lower data rates associated with long-loop architectures may require more complex decoding schemes than the high data rates associated with short-loop architectures. As a result, conventional hardware-based techniques may be unable to support the varying decoding complexity. While certain approaches have been made at implementing modem technology in software, which can be re-configured more easily, operating system (OS) stability has been a cause for concern. As a result, conventional software modems have not proven to be a viable alternative. There is therefore a need for an approach to implementing a modem receiver that is programmable with regard to the encoding scheme used and does not result in OS instability.